(NOT APPLICABLE)
The present invention relates to vision enhancing optical systems and, more particularly, to a lightweight efficiently focusable optical system, especially for use by low vision persons such as in association with eyeglasses.
Vision enhancing systems for low vision individuals have made significant advances in the past years. As shown by U.S. Pat. Nos. 4,704,000 and 5,680,195, vision enhancing systems now may be provided that are light enough to be mounted on a user""s eyeglasses. As shown in an article entitled xe2x80x9cSelf-Focusing Infrared Telescope Glasses May Restore Sight to Millions,xe2x80x9d Electronic Design, Goldberg, Apr. 14, 1997, such low vision systems may include auto-focusing. While enormous strides have been made, it is desirable to provide an optical system for low vision individuals that is even lighter and has more effective and efficient focusing and that is well suited for auto-focusing.
One system that attempts to achieve this object is described in U.S. Pat. No. 6,065,835, which is incorporated herein by reference. In this system, a mirror cluster includes two mirrors that are mounted at an angle of about 90xc2x0 to each other and for substantially linear movement. With the 90xc2x0 mirror cluster, two units of focus are achieved for every one unit of travel, making focusing quicker and easier. The patent recognizes that while the same basic results could be achieved by moving prisms instead of mirrors, mirrors are much lighter in weight than prisms and therefore are much more suitable to wearable vision systems, particularly those that must be light enough to be mounted on eyeglasses. This system, however, must be sized to accommodate the linear movement of the mirror cluster. In a binocular system, the linear movement of two mirror clusters must be accommodated. As a consequence, the size of the device is larger than desirable, and the device itself tends to interfere with normal and peripheral vision.
With the system of the present invention, it is an object to provide a lightweight, efficiently, universally and effectively focusable optical system, especially for use by low vision persons such as in association with eyeglasses. It is a further object to provide such a system within a compact housing that minimizes interference with central and peripheral vision.
It is yet another object to ensure that a magnified image viewed by the system at any distance appears in the same spatial location as normally viewed except for image size.
In an exemplary embodiment of the invention, a vision enhancing optical system includes an objective lens disposed in an optical path, an eyepiece lens disposed in the optical path, and a mirror cluster disposed in the optical path and having first and second substantially planar mirrors that are disposed at an angle of substantially 90xc2x0 relative to each other. The mirror cluster is pivotable about an axis substantially perpendicular to the optical path at the mirror cluster. The system may further include a third mirror disposed in the optical path reflecting incoming light toward the objective lens. A fourth mirror may be disposed in the optical path reflecting the incoming light toward the mirror cluster. In sequence, the system preferably includes the third mirror reflecting incoming light toward the objective lens, the objective lens, the fourth mirror reflecting the incoming light toward the mirror cluster, the mirror cluster, and the eyepiece lens.
The first and second mirrors of the mirror cluster are preferably coupled to arms of a bracket disposed substantially 90xc2x0 relative to each other. In this context, the bracket is coupled with a rotatable mirror arm. The system includes structure for rotating the mirror arms such as a motor or the like. The third mirror disposed in the optical path that reflects the incoming light toward the mirror cluster is also pivotable relative to the objective lens. In this context, the mirror arm supporting the third mirror preferably includes a cam, and the third mirror is coupled with a cam follower engaging the cam. The position of the third mirror is adjusted based on a position of the mirror arm.
The optical system may be a binocular or monocular system. In one embodiment of the monocular arrangement, an entrance mirror reflects incoming light toward the mirror cluster, wherein the entrance mirror is spaced from the mirror cluster by a distance substantially corresponding to the distance between a person""s eyes. In a second embodiment, an entrance mirror reflects light toward a prism. In both embodiments, the entrance mirror is preferably pivotable relative to the optical path to enable image position correction as previously described.
In another embodiment, an eyepiece houses the eyepiece lens, and the optical system is attachable to a frame of a pair of glasses. When the optical system is attached to the glasses frame, only the eyepiece and eyepiece lens impinge an area inside the glasses frame.
In another exemplary embodiment of the invention, a binocular vision enhancing optical system includes first and second objective lenses disposed in first and second optical paths, respectively; first and second eyepiece lenses disposed in the first and second optical paths, respectively; and first and second mirror clusters disposed in the first and second optical paths, respectively. Each of the first and second mirror clusters includes first and second substantially planar mirrors that are disposed at an angle of substantially 90xc2x0 relative to each other. The mirror clusters are pivotable about an axis substantially perpendicular to the respective optical paths at the mirror clusters.
In yet another exemplary embodiment of the invention, a vision enhancing optical system includes a pair of glasses including a frame and the vision enhancing unit according to the invention secured to the glasses frame.